Method of building roads



Patented Jan. 7, 1936 UNITED STATES I 2,026,989 lvnirnon OF BUILDINGnorms Hermann Plauson, Freiburg, Germany, assignor, by mesneassignments, to T. It. 0. Corporation, Wilmington, Del., a corporationof Delaware No Drawing. Original application August 12,

19 31, Serial No. 556,616. Divided and this application January 19,1934, Serial No. 707,341. In Germany August 15, 1930 This application isa division of my original application Serial Number 556,616, filedAugust 12, 1931.

It is also a continuation-in-part of my pending application, Serial No.492,875, filed November 1, 1930, the claims of which are directed toroad-pavings whilethe present application is ..directed to methods ofmaking road-pavings. I.

4 Claims.

This invention refers to a method of road 0 building and has for itsobject to produce a ballast road of the well known macadam type in asimpler and more efficient way than was hitherto possible.

. My invention has particular reference to the production of roadcoverings in which the ballast or other mineral matter is cementedtogether by a kind of mortar containing hydraulic binders in combinationwith bituminous substances including all kinds of asphalt, road andother tar, pitch; etc.

According to the present invention and to the preferred mtfiie ofpractising same I arrange on the roa o be covered, which may havepreviously been prepared in any suitable manner, one or 26 severallayers of ballast stone of some suitable kindr fthereupon place on thisballast layer the mortar mentioned above in a dry and pulverulent stateand then cause this mortar to enter the interstices and cavities betweenthe bal- 30 last stones by sprinkling the same with water to produce afluid suspension of the mortar and by compacting the whole by rolling asusual, thereby forcing the mortar deeply and firmly into the ballaststone layer and causing the individual stones to be cemented together bythe mortar as it sets under the action of the water.

In thus placing a layer of the dry pulverulent mixture of a hydraulicbinder and a bituminous substance onto the ballast layer and uniting theballast and the mortar by adding water and rolling, similar to the wellknown manner of proceeding in the case of waterbound ballast roads, r Iobtain the advantage that the old known process of producing macadam orballast road coverings can be retained although the binding matter isnot ordinarily lime, cement, concrete or the like, but a mixture of oneof these or other hydraulic binders with a bituminous substance of thekind mentioned above. This advantage is of great importance as I am thusenabled to construct a practically perfect and highly enicient roadwithout large machinery or skilled labor as a result of which the costis comparatively low.

As compared with the methods hitherto used PATENT OFFICE in which ahydraulic binder as such formed the means for cementing the ballaststones together, I obtain a road covering, which owing to the presenceof the bituminous additions to the binder is more elastic and thereforemore durable and less affected by atmospheric influences.

All methods hitherto in use in the construction of rolled ballast roadscan be applied in the practice of my invention. I may, for instance,place the ballast layer onto the road and roll it, the pulverulentmortar mixture being then strewn on the ballast layer, spread thereonand in the interstices by forking and washing, whereupon the covering isrolled.

I may, however, alsostart by spreading on the road the dry pulverulentmortar, arranging thereon a layer of ballast stones, which are thereuponrolled, whereupon water is added to start the binding action of themortar, whereupon a second rolling is effected. In this method I prefersuperposing several layers of mortar and bal last.

I may, however, also mix the pulverulent mortar described above in situwith sand and convert this mixture by the addition of water into asludge, which is now added to the ballast in the usual manner.

Example 1 I first prepare the pulverulent mortar by intimately mixing200 kilograms hydraulic lime with 40 kilograms normal road tar in amill. The powder thus obtained is then mixed with another 200 kilogramshydraulic lime and this mixture is intimately mixed in a suitable mixingap- 35 paratus with 500 kilograms normal Portland cement.

I then arrange on the suitably prepared road a layer of ballast stones,the individual stones being about 3-5 centimetres in diameter, and I 40slightly plane this layer by rolling. I now mix the pulverulent mortarwith a corresponding quantity of sand, for instance in the proportion ofl sand to 3 mortar, and arrange a layer of this mixture on the ballastlayer, about 12 kilograms of the 45 mortar being spread on each squaremetre. The mortar is now driven into the interstices and cavitiesbetween the stones by forking, brushing or the like and water is thenadded, whereupon the covering is finally rolled. 50

Example 2 I prepare the pulverulent mortar by heating 200 kilogramsfinely ground trass to -100 C. and grinding same in an edge mill withkilo- 55 grams molten asphalt. I allow the mixture to cool down andgrind it to powder in a disintegrator or the like. I now intimately mixwith 300 kilograms of this powder 500 kilograms cement and another 200kilograms trass reduced to the finest powder in a disintegrator or thelike. I mix the pulverulent motar thus obtained with sand in theproportion of about 1:3 and arrange it on the suitably prepared road ina layer about 2-3 centimetres high. On this layer I spread a layer ofloose ballast stones, which are slightly forced in by rolling. I thenadd water and continue rolling, thereby causing the mortar sludge torise between the stones. In the covering thus obtained I may arrangeanother or a plurality of compounds layers prepared in a similar manner.

As indicated in my acknowledged copending application Serial No.492,875, of which the present application is a continuation-in-part, anadvantageous method, within the scope of the present invention,comprises arrangingon the road a. layer of ballast stones and a, dryuniformly bituminated pulverulent intimate mixture of a hydraulic binderand not more than seven per cent, calculated on the weight of thebinder, of a bituminous substance, compressing the layer of stones andmortar by rolling so as to fill the interstices between the stores withthe mortar and adding water to cause the bituminated hydraulic binder toset in situ thereby uniting the ballast stones into a monolithic block.The percentage of bituminous material called for by the claims is basedon the weight of the hydraulic binder which, of course, is mixed withthe usual amounts of sand, etc. for preparation of the mortar. Themortar may be prepared from an initially pulverulent intimate mixture ofcement, another hydraulic binder, selected from a class consisting ofhydraulic lime and gypsum, and not more than seven per cent, calculatedon the weight of hydraulic binders present, of a bituminous sub- 5stance.

Various changes may be made in the details disclosed in the foregoingspecification without departing from the invention or sacrificing theadvantages thereof. 1

What I claim is:

1. The method of making 2, rolled ballast road which comprises arrangingon the road a layer of ballast stones and a dry uniformly bituminatedmortar prepared from a pulverulent intimate 15 mixture of a hydraulicbinder and not more than seven per cent, calculated on the weight of thebinder, of a bituminous substance, compressing the layer of stones andi'nortar l u gW' to fill the interstices between the stones with the 20mortar and adding water to cause the bituminated hydraulic binder to setin situ thereby uniting the ballast stones into a monolithic block.

2. The process of claim 1 wherein the dry uniformly bituminated mortaris laid on top of the 5 ballast stones, water is then added, followed byrolling to cause the hydraulic mortar to fill the interstices andcavities between the ballast stones:

3. The process of claim 1 wherein the dry uniformly bituminated mortaris first laid, the bal- 30 last stones are placed over said mortar,water is added and the road is rolled.

4. The process of claim 1 wherein the .dry uniformly bituminated mortaris mixed with water to make a sludge prior to laying it.

HERMANN PLAUSON.

